Earth-drilling bits



Feb. 25, 1969 F. 1.. BENNETT EARTH-DRILLING BITS Sheet Filed May 19,1967 INVENTOR Fred L. Bennett fi a fi Y ATTORNEYS Feb. 25, 1969 F. L.BENNETT 3,429,390

EARTH-DRILLING BITS Filed May.l9. 1967 Sheet 3 of 5 INVENTOR Fred L.Bennett ATTORNEYS Feb. 25, 1969 Filed May 19, 1967 F. L. BENNETTEARTH-DRILLING BITS Sheet 39 I ff INVENTOR Fred L. Bennett ATTORNEYS F.L. BENNETT Feb. 25, 1969 EARTH-DRILLING BITS Sheet 4 015 Filed May 19,1967 Fl 6. l 7

F I G. I l

INVENTOR Y 7 Fred L. Bennett I, d I v BY W 4 I ATTORNEYS v Feb. 25, 1969F. L. BENNETT 3,429,390

EARTH-DRILLING BITS Filed May 19, 1967 Sheet 5 of s INVENTOR Fred L.Bennett ATTORNEYS 3,429,390 EARTH-DRILLIN G BITS Fred L. Bennett,Clarksville, Ark., assignor to Supercussion Drills, Inc., San Antonio,Tex., a corporation of Texas Filed May 19, 1967, Ser. No. 639,792

US. Cl. 175343 10 Claims Int. Cl. E21b 9/08; E21c 13/02 ABSTRACT OF THEDISCLOSURE Earth-drilling bits having flat conical drilling facesinclined at an angle to the axis of the drill hole with nontrackingdrilling elements, means for holding only a portion of the periphery ofthe bit against the wall of the drill hole, having a unique gyratorymovement and unique bearing and sealing means and being particularlyadapted for use with percussion and turbine types of drilling rigs.

BACKGROUND OF THE INVENTION Field of the invention The invention wasmade to answer the need for an earth-drilling bit particularly adaptedwith bearing and structure sufficiently rugged for use with percussionand turbine types of drilling rigs, Previous bits have not been able toWithstand either heavy impact forces of percussion type drilling rigs orthe rotational speeds of turbine type rigs.

Description the prior art No prior art is known except the several US.patents issued to Zublin, the members of which are not known.

SUMMARY OF THE INVENTION The invention relates to earth-drilling bitshaving angularly-disposed gyratory bit members with relatively flatconical drilling faces with a multiplicity of unequallyspaced drillingelements thereon, the bit members regressing slowly as the bits arerotated or, in other words progressing slowly in the opposite directionto the direction of rotation of the entire bit, with which any type ofdrilling fluid may be used and which are especially adapted for use withpercussion and turbine types of drilling rigs. The various forms of theinvention include novel lubricant seals, heavy impact and bit-loadbearings means for selectively enhancing the flow of drilling fluidthrough the bit or terminating the flow to hold the drill string full ofdrilling fluid under pressure. The bits have stand-off means for holdingonly a portion of the periphery of the bit member against the wall ofthe drill hole so that the bits drill bore holes larger in diameter thanthe bits themselves.

A construction designed to carry out the invention will be hereinafterdescribed, together with other features of the invention.

The invention will be more readily understood from a reading of thefollowing specification and by reference to the accompanying drawings,wherein examples of the invention are shown.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical, longitudinal,sectional view of an earth-drilling bit constructed in accordance withthe invention and showing a form thereof adapted to selective enhancingthe flow of drilling fluid through the bit, showing the enhancing meansclosed,

FIG. 2 is a vertical, longitudinal, sectional, fragmentary view of thebit of FIG. 1, showing the enhancing means open,

nited States Patent 0 3,429,395 Patented Feb. 25, 1969 FIG. 3 is a viewin perspective of the core of the flowenhancing means,

FIG. 4 is a bottom plan view of the bit,

FIG. 5 is a horizontal, cross-sectional view taken on the line 5-5 ofFIG. 1,

FIG. 6 is a vertical, longitudinal, sectional fragmentary view of amodification of the bit showing the valve means for holding pressure inthe drill string, the valve means being open,

FIG. 7 is a view similar to FIG. 6, the valve means being closed,

FIG. 8 is a bottom plan view of the valve means of FIGS. 6 and 7,

FIG. 9 is a vertical, longitudinal, sectional view of a furthermodification of the invention in which the anvil or body member of thebit is isolated percussion-wise from the bit case and the drillingstring,

FIG. 10 is a horizontal, cross-sectional view taken on the line 1010 ofFIG. 9,

FIG. 11 is a vertical, longitudinal, sectional view of yet anothermodification of the invention showing unique stabilizing bearings,

FIG. 12 is a horizontal, cross-sectional view taken on the respectiveline 1212 of FIG. 11,

FIG. 13 is a vertical, longitudinal, sectional view of still anothermodification of the invention showing structures 'for utilizing thrustbearings in the bits to any desired extent and novel lubricant seals forprotecting the bearings,

FIG. 14 is a horizontal, cross-sectional view taken on the line 14-14 ofFIG. 13,

FIG. 15 is a bottom plan view of the bit of FIG. 13,

FIG. 16 is a vertical, longitudinal, sectional, fragmentary view of amodified form of the thrust bearings of the bit of FIG. 13,

FIG. 17 is a vertical, longitudinal sectional, fragmentary view of afurther modification of the thrust bearings of the bit of FIG. 17, and

FIG. 18 is a horizontal cross-sectional view taken on the line 1818 ofFIG. 17.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawing, in FIG. 1 thereis shown a form of the invention particularly adapted for use withpercussiontype drilling rigs in which a percussion hammer 10 isreciprocated vertically in a percussion tool case 11 in order to impactwith great force, rapidly and forcefully, upon the upper end of an anvil12 constituting the upper end of the earth-drilling bit. The percussiontool itself is not shown but is of a type known in this art in which thefunction of the percussion tool is dependent upon a creation of backpressure upon the drilling fluid, which may be air, natural gas,drilling mud or any other suitable or desirable type of drilling fluidand upon the downward flow of which, under pressure through the flowpassage 13 of the hammer 10 and the flow passage 14 of the anvil 12, thepercussion tool is dependent for operation. Upon removal of such backpressure on the drilling fluid, the percussion tool ceases to function,and the hammering or delivery of percussion strokes is stopped.

The anvil 12 constitutes the upper end of a drill body member 15 and isin the form of an upstanding screw threaded pin 16 screw-threadedlyconnected to the lower end of the case 11 which, in turn, is connectedto the lower end of the drill string (not shown). The body member 15 isshouldered at 17 for abutment with the lower end of the case, and belowthe shoulder 17, the body member 15 carries a plurality of external,radially outwardly-extending stand-oft members 18, preferably hardfacedfor engagement with the wall of the drill hole to hold the body member15 centered therein. The stand- 3 off members may be shoes, rollers orany other suitable or desirable type of structure which will function tocenter the body member in the drill bore.

The body member is provided on its lower end with a reduced, cylindricalpin 19, eccentrically oifset with respect to the axis of the bodymember, and extending downwardly at an angle to the longitudinal axis ofthe body member, which angle may be on the order of magnitude of 35 orgreater or lesser.

A downwardly flared drill bit member 20 is provided with a cylindricalsocket 21 at its upper end for receiving the pin 19, the bit memberbeing held on the pin by an annulus of retaining balls 22 engaging in ahardened race 23, of semicircular cross section, formed in the wall ofthe socket 21 intermediate its end, and in a hardened race 24 ofvertically elongated semicircular cross section formed at acorresponding elevation on the outer periphery of the pin 19.

The annulus of the retaining balls 22 is inserted into the two racesthrough a radial opening 25 in the bit member aligned with the race 23and closed by a screw threaded pin 26 after the bearing balls have beenplaced in position. The vertically elongated configuration of the race24 permits limited reciprocal movement of the bit member 20 upon the pin19.

The body member 15 has a downwardly facing shoulder 27 surrounding theupper end of the pin 19, and a hardened race 28 is provided thereincomplementary with a similar race 29 formed in the upper end of the bitmember. An annulus of thrust bearing balls 30 is received in the tworaces. Further, the lower extremity of the pin 19 is cut away at itsmargin to form a hardened race 31, and the bottom of the socket 21 iscut away at its margin to form a hardened race 32. An annulus ofsuitable thrust bearing balls 33 are received in the races 31 and 32.

The bit member has a valve core or member 33 extending axially andupwardly from the bottom of the socket 21, the upper end of the valvemember 33 being beveled or chamfered, the lower portion of the member 34being surrounded by an annular drilling fluid flow passage 35 from whicha plurality of rectilinear flow passages 36 extend angularly anddownwardly to the drilling face 37 of the bit member and register withflow grooves 38 extending radially outwardly from the passages 36 to theouter periphery of the drilling face, the grooves being notched upwardlyat their outer ends as shown at 39.

The drilling face 37, and this is true of all forms of the invention, isapproximately flat, approximately flat as used herein meaning anabsolutely flat face or one that has the shape of an almost flat,downwardly facing cone, the apex angle of the cone being of the order of25 or more. The drilling face carries a multiplicity of irregularlyspaced drilling elements which may have the form of hard metal inserts40 having hemispherically shaped lower drilling faces 41. As shown inFIG. 4, the

grooves 38 divide the drilling face 37 into sectors, and the drillingelements 40 are irregularly spaced, either radially or circumferentiallyin each of the sectors with respect to the other sectors. Thus, as thedrilling elements revolve over the bottom of the bore hole, they areprevented from tracking one "another in a gear-like action, and moreeffective and eflicient action is obtained.

The stand-off members 18 and the angular and offset disposition of thebit member, cause only a portion of the periphery of the drilling facefrom engaging the wall of the well bore, so that only a sector ofpossibly 20 to circumferentially, extent of the drilling face isdrilling at any one time. The bit member and the drilling face thereofis less in diameter than the bore hole which it drills, but the gyratorymovement of the drill member as it drills causes the entire drillingface to be employed for drilling in successive sectors and to drill abore hole having a bottom of a slightly conical shape when a flat oronly slightly conical drilling face is employed and a flat face when aslightly more conical drilling face is used.

This conical shape of the drill bore bottom, as shown at 37' in FIG. 1,functions also to aid in urging the bit toward one side of the borehole. The bit member is necessarily of less diameter than the bore holesince otherwise the drilling face, being inclined, would drill atdiametically opposite points and the desired drilling action would notbe achieved.

If the drill string and thus the case 11 and body member 15 is revolvedin one direction, by reason of the angle and offset position of the bitmember the latter is caused to turn or progress in the oppositedirection at a somewhat slower rate, possibly at the rate of 1revolution to each l040 revolutions of the drill string. In this manner,the bit member undergoes a gyratory action, revolving slowly over thebottom of the bore hole, drilling all portions of the bottom of the borehole with all portions of the drilling face under whatever load may beapplied to the bit through the drill string as well as the quite sizablepercussion impact delivered by the hammer 10.

The drilling fluid flow passage 14 extends downwardly through the body15 into the bit 19 and opens into one side of an enlarged cylindricalflow passage 42 extending downwardly to the lower end of the bit 19 inregistry with the annular flow passage 35. Valve means 43 in the form ofa cylindrical spool, as shown in FIG. 3 is axially movable in thepassage 42 and loosely confined therein by the snap rings 44 and 45 soas to be capable of undergoing limited axial movement in the flowpassage 42. The valve member 43 has a rather large axial flow passage 46surrounded by a number of somewhat smaller longitudinal flow passages47, the flow passage 46 being of less diameter than the valve member 34.As noted, hereinabove, the type of percussion tool with which theparticular bit shown in FIG. 1 is to be used if for operation on theexistence of back pressure on the drilling fluid and will ceaseoperating when such back pressure is removed. The structure of themodification of FIG. 1 which achieves this function in that when weightfrom the drill string is applied to the body member 15 and the pinmember 19 is in its downwardmost position in the socket 21, the valvemember 34 will engage and close off the center passage 46 of the valvemember 43, as shown in FIG. 1, and drilling fluid will be passing onlythrough the relatively restricted passages 47, thereby creating thenecessary back pressure. When, however, the drill string is lifted, thebit member 20 drops upon the pin 19 into the position shown in FIG. 2,allowing the valve member 34 to disengage from the valve 43, opening thepassage 46 to the flow of drilling fluid, thereby removing the backpressure and causing the percussion tool to cease functioning. Thus, thepercussion tool may be placed in and out of operation at will by raisingand lowering the drilling string.

It is sometimes desirable to be able to close off the drilling fluid inthe drill string when drilling is momentarily halted for any reason,especially when gas such as air or natural gas is being employed at arelatively high pressure as the drilling fluid. If gas is being employedas the drilling fluid under a pressure of 500-1000 pounds per squareinch, the loss of this gas under pressure when drilling is halted wouldnecessitate a considerable period of time and expenditure of energy tobuild up the pressure when drilling is resumed. Drilling systems of thistype normally have a back-pressure valve at the top of the drill string,but there is nothing to prevent the escape of the drilling fluid underpressure at the lower end of the drill string. The structure shown inFIGS. 6 and 7 makes provision for closing off the string and includes acylindrical spool 48 which replaces the spool 43 in the flow passage 42and has a snug sliding fit therein. The spool 48 is held in the passage42 by upper and lower snap rings 49 and 50 and is provided with an axialbore 51 with a valve seat 52 at its upper end. A fluted valve core 53 isslidably positioned in the bore 51 formed with a plurality oflongitudinal flow passage grooves 54 in its outer face through which thedrilling fluid may pass and which also function to provide a backpressure on the drilling fluid. The valve core has a valve face 55 atits upper end adapted to engage the valve seat 52 and normally heldspaced thereabove by the engagement of the valve means 34 when the bodymember and the bit member are collapsed on one another in drillingposition, as shown in FIG. 6. When, however, the drill string is lifted,and the body member and bit member separate partially, as shown in FIG.7, the valve member 34 moves downwardly permitting the valve face 55 toengage the valve seat 52, thus closing off the lower end of the drillstring and trapping the drilling fluid under pressure in the interiorthereof. Thus, when drilling is resumed, it is not necessary to build upthe pressure of the drilling fluid again, and the needless and expensiveexpenditure of time and energy is avoided.

In the previously described forms of the invention, the hammer 10,although of appreciable mass, is required to deliver its impact strokesagainst the mass of not only the anvil 16 and the body and bit membersbut also against the mass of the case 11 and the entire drill stringwhich is connected thereto. It is much more desirable to apply theimpact blows of the hammer against only the body and bit members so thatmuch greater forces are delivered to the drilling face of the bit, andsuch a structure is shown in FIGS. 9 and 10.

In this form of the invention, which is substantially identical to thosepreviously described, except that the spools 43 and 48 are omitted, theupper end of the body member 15 is not connected directly to the case11, but instead, it is reduced in diameter and formed into an upstandingcylindrical shank 44 slidably received in an externally screwthreadedsleeve 56, which, in turn, is screw threadedly connected to the case 11.At the upper end of the sleeve 56 are suitable sealing and/or bearingrings 57 and 58, above which is a split retaining ring 59 having aninwardly directed annular flange 60 received in a circumferential groove61 in the upper end of the shank 55 to retain the shank 55 within thesleeve 56. The ring 59 is connected in any suitable fashion to the case11, and the groove 61 is of greater axial length than the flange 60 soas to permit limited axial move ment of the shank 55 within the sleeve56. Any suitable back pressure or flow restricting means 62 is removablypositioned at the upper end of the drilling fluid flow passage 63 of theshank 55. For getting rotation from the sleeve 56 to the shank 55 andthe body member 15, the two elements are splined together by a numeralof cylindrical elements 64 received in recesses 65 and 66 cut in theshank and sleeve, respectively, the recesses being of greater lengththan the elements 64 so as to permit relative longitudinal movementbetween the shank and the sleeve.

With this structure, the impact blows of the hammer are directed only tothe shank 55, the body member 15 and the bit member 20, and since thebit assembly can move relative to the case and the drill string suchimpacts are not transmitted to the drilling string so that their forceis directed solely to the drilling assembly for more effective andeflicient drilling.

It may be desirable in some instances to provide a small angular flowpassage 67 leading from the drilling fluid flow passage 63 or any of theother drilling fluid flow passages into the space at the upper end ofthe bit member inwardly of the bearing balls 30 to provide lubricationand/or cleaning of the several bearings.

An alternate structure of the bit is shown in FIG. 11 in which anannulus of vertical needle bearings 68 and 69 are situated at the upperand lower ends of the pin 19, respectively, for stabilizing the bitmember upon the pin, it being noted that either or both of the needlebearings 68 and 69 may be employed, and that the lower bearing balls 33are shifted inwardly toward the flow passage 14', or may be omittedentirely.

A preferred form of the invention is shown in FIGS. 13, 14 and 15 inwhich the grooves 38 are omitted, and only a plurality of upwardlyinclined peripheral notches 70, equivalent to the cut away portions 38of the bit shown in FIG. 1, are provided in the outer margin of thedrilling face 71.

The body member 72 has an angularly directed flow passage 73' openingdownwardly into a counter bored socket 74 formed eccentrically of thebody member 72 and extending angularly to the longitudinal axis thereof.An annular groove 75 is formed in the top of the uppermost and narrowestportion 76 of the socket 74 and receives a grease sealing ring 77 havingin its upper and lower faces V-shaped sealing grooves 78 to providechevron-type lubricant seals.

Below the uppermost portion 76, the socket 74 is enlarged at 79 toreceive an annulus of vertical needle-type, stabilizing bearings 80, andthe retaining balls 22 are provided therebeneath for retaining the bitmember in the socket 74 as previously described.

Below the retaining balls 22, the socket 74 is further enlarged to forma downwardly facing shoulder 81 receiving a bearing ring 82, dual rollerbearings 83 and a lower bearing ring 84. Therebelow, the socket isfurther enlarged at 85 to receive needle-type stabilizing bearings 86and is formed with a second recess 87 which receives a lubricantretaining ring 88 substantially identical to the sealing ring 77. Asuitable lubricant may be introduced into the space between the seals 77and 88 through the passage 25 and retained therein by the seals and thescrew-threaded pin 26. It is noted that the lubricant in the bearingarea and the drilling fluid externally of the bit will equalize inpressure through the threads of the screw-threaded plug 26.

The bit member 89 has its exterior stairstepped upwardly having a firstshoulder 90 underlying the lower end of the body member 72, a firs-tcylindrical face 91 engaging the sealing ring 88, a second upwardlyfacing shoulder 92 underlying and supporting the bearings 86, a secondcylindrical face 93 engaging the bearings 86, a third upwardly facingshoulder 94 underlying the bearing ring 84, a third cylindrical face 95adjoining the bearings members 82, 83 and 84 and recessed to receive theretaining balls 22, Above the retaining balls 22 the upper portion ofthe bit member, which now constitutes an upstanding shank 96, is formedwith a further upwardly facing shoulder 97 underlying and supporting thebearings 80 and a further face 98 engaging the bearings 80 and thesealing ring 77. It is quite obvious that the shoulders 81 and 94 may bespaced apart as far as desired so as to accommodate any desired numberof thrust bearings superposed therebetween.

The bearings 82, 83 and 84 may be replaced with a metal to metal bearingas shown in FIG. 16. In a metal to metal bearing, the metals must bedifferent or at least, different alloys, thus, assuming the body and bitmembers to be alloy steels, the upper metallic bearing ring 99 could beformed of tool steel and the lower bearing ring 100 formed of bronze,with grooved faces for the reception and passage of lubricatingmaterial. At the beginning the sliding or bearing faces would be betweenthe rings 99 and 100, but as these abutting faces wore and galled thebearing face would shift either to the ring 99 and the shoulder 81 or tothe ring 100 and the shoulder 94. When the first of these faces was wornand galled, the bearing then passes to the other of said pairs of faces.By this means the equivalent of three bearings is obtained with thebearing function passing successively from one pair of faces to thenext. Of course, more than two of the bearing rings may be used.

The configuration of the drilling elements or inserts 101 in this formof the bit is somewhat modified and a specific example thereof is shownin FIG. 15. In this particular configuration there are eight of theperipheral notches 70 spaced equally around the circumference of theface 71 with eight peripheral drilling inserts 102 spaced equally aroundthe margin of the drilling face, one between each pair of notches.inwardly of the inserts 102 are four drilling inserts 103 radiallyaligned with the inserts 102 and inwardly thereof three inserts 104spaced radially inwardly of certain of the inserts 103. A single insert105 is positioned inwardly of the inserts 104 and one single drillinginsert positioned centrally of the drilling face with four drillingfluid flow passages 107 extending through the drilling face 71intermediate the pairs of the notches 70. Obviously greater or lessernumbers of the drilling inserts may be used, and differentconfigurations or spacings employed.

It is readily apparent that this configuration provides the largestnumber of cutting inserts at the edge of the drill hole where most ofthe drilling is to be done with progressively fewer inserts radiallyinwardly to the center of the bit to accommodate the successivelydecreasing areas of the bore hole to be drilled, The relatively sparsenumber of drilling inserts provides uncluttered spaces through which thedrilling fluid readily flows to the notches 70, sweeping over thesurface being drilled and keeping both it and the drilling face clear ofdrill material.

The body member 72 has on its periphery above the lower end thereof aplurality of standoff means 108 disposed at an angle, for instance, 45with respect to the longitudinal axis of the bit, the standoff means 108being spaced apart to provide fluid flow passages therebetween. Thestandoff means may be arranged in any desired pattern. The standoffmeans may be hard-faced guide shoes, rollers or any other suitablestructure. In addition, standotf rollers (not shown) could be providedin the body member 72 above the standoff means 108.

A final form of the bit is shown in FIG. 17 this form of the bit beingsubstantially identical to that shown in FIG. 13, but the bearings 82,83 and 84 being replaced by one or more superposed ball bearings 109which function as thrust bearings.

Various changes and modifications in the methods and products outlinedand disclosed herein may be made within the scope of the claims appendedhereto without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. An earth-drilling bit including a bit body member a drill bit memberconnected to the body member, one of the members having a shank, theother of the members having a socket receiving the shank, said bodymember and said bit member vertically reciprocable with respect to oneanother, said body member and said bit member having registeringdrilling fluid flow passages, the bit member having a single one-piecedrilling face and being rotatably mounted on the body member, the bitmember having its longitudinal axis inclined with respect to thelongitudinal axis of the body member and having an approximately flatdrilling face, a drilling fluid flow member carried by one of saidmembers having at least one drilling fluid flow-restricting passage andat least one drilling fluid flow-enhancing passage, valve means carriedby the other member registering with the flow-enhancing passage forclosing the same when the members are collapsed upon one another so asto permit the flowrestricting passage to restrict the flow of thedrilling fluid and for opening the flow-enhancing passage when themembers are moved apart to enhance the flow of the drilling fluid, andstand-off members on the outer surface of the body member for holdingone portion only of the periphery of the bit member against the wall ofthe drill hole whereby the drilling face of the bit is smaller indiameter than the hole it drills.

2. An earth-drilling bit as set forth in claim 1 wherein the shank is onthe bit member and the socket is on the body member.

3. An earth-drilling bit as set forth in claim 1 wherein the shank is onthe bit member and the socket is on the body member, the shank andsocket having shoulders facing each other, and a plurality of thrustbearing members confined between the shoulders.

4. An earth-drilling bit as set forth in claim 1 and lubricant sealingrings between the upper and lower extremities of the shank and socket,each sealing ring having V-shaped chevron-type sealing grooves in itsupper and lower faces.

5. An earth-drilling bit as set forth in claim 1 wherein the drillingface of the bit member is divided into circumferential sections andcarries a multiplicity of earthdrilling elements, the drilling elementsof the sections being spaced apart on the drilling face by differingdegrees whereby the earth-drilling elements do not track one another asthe bit revolves.

6. An earth-drilling bit as set forth in claim 1 and vertically-disposedannuli of needle stabilizer bearings between the upper and lowerextremities of the shank and socket.

7. An earth-drilling bit as set forth in claim 1 andcircumferentially-spaced upwardly-inclined notches about the peripheryof the drilling face.

8. An earth-drilling bit as set forth in claim 1 andcircumferentially-spaced upwardly-inclined notches about the peripheryof the drilling face, a first peripheral set of drilling elements on thedrilling face, one between each pair of notches, a second set of alesser number of drilling elements spaced radially inwardly of the firstset, a third set of a still lesser number of drilling elements spacedradially inwardly of the second set, at least one drilling elementspaced radially inwardly of the third set, and at least one drillingelement positioned centrally of the drilling face.

9. An earth-drilling bit as set forth in claim 1, and thrust bearingsbetween the body member and the bit member comprising at least a pair offlat superposed rings formed of metals dissimilar to each other and tothe metal or metals of which the body member and bit member are formed,

10. An earth-drilling bit including a bit body member, a drill bitmember connected to the body member, one of the members having a shank,the other of the members having a socket receiving the shank, said bodymember and said bit member vertically reciprocable with respect to oneanother, said body member and said bit member having registeringdrilling fluid flow passages, the bit member having a single one-piecedrilling face and being rotatably mounted on the body member, the bitmember having its longitudinal axis inclined with respect to thelongitudinal axis of the body member and having an approximately flatdrilling face, valve means carried by one of the members for movingbetween two positions for permitting flow of the drilling fluid in oneposition and shutting off flow of the drilling fluid in the otherposition, valve accuating means on the other member for opening thevalve means when the members are collapsed upon one another and forclosing the valve means when the members are moved apart, and stand-offmembers on the outer surface of the body member for holding one portiononly of the periphery of the bit member against the wall of the drillhole whereby the drilling face of the bit is smaller in diameter thanthe hole it drills.

References Cited UNITED STATES PATENTS 1,254,267 1/1918 Pickin -3761,334,632 3/1920 Pickin 175-376 X 1,784,476 12/1930 Zublin 175376 X1,945,240 1/1934 Tupica 175-376 X 2,013,839 9/1935 Pickin 175376 X2,154,032 4/1939 Catland 175-376 X 2,207,188 7/1940 Zublin 175376 X2,598,518 5/1952 Dufilho 175376 X NILE C. BYERS, JR., Primary Examiner.

